Ketene-S, S-acetals-V: the reactions of α-keto and α-cyanoketene-S, S-acetals with guanidine and thiourea: a new general synthesis of alkoxy-pyrimidines
The ketoketene-S, S-acetals (5a–c) react with guanidine and thiourea in the presence of alcoholic sodium alkoxides to give 2-amino-and 2-mercapto-4-alkoxy-5-aryl-6-methyl- pyridimidines (6a–k) respectively in good yields. The α-cyanoketene-S, S-acetals (9a–d) similarily gave 5-substituted-2, 4-diamino-6-alkoxy-pyridimidines (10a–e) with guanidine in 50–60% overall yields. The unexchanged 2, 4-diamino-5-p-chlorophenyl-6-methylthio- ...
